Aircraft Brake Control Unit Calibration for Idle Position Accuracy

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Solution Overview

Problem

Aircraft brake systems face challenges in accurately determining the idle pedal position due to installation tolerances and variations, leading to potential incorrect application of braking forces.

Innovation Solution

The implementation of a brake pedal assembly with a linear variable differential transformer (LVDT) and a brake control unit (BCU) that includes both hardware and software threshold voltages, allowing for calibration and offset adjustments to ensure precise determination of the idle pedal position, thereby preventing unintended braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a fixed hardware threshold voltage is used to determine idle pedal position, then the brake control system is simple to implement, but it cannot account for installation tolerances and variations leading to incorrect braking

Engineering Contradiction:
Improvesimplicity of brake control systemVSAvoidaccuracy of idle pedal position determination
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the threshold voltage parameter from a fixed hardware value to a software-configurable value that can be calibrated during installation. This allows the threshold to be adjusted to match actual installation conditions, accounting for tolerances and variations in the mechanical assembly while maintaining the simplicity of the overall control system.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If software calibration and offset adjustments are added to account for installation variations, then measurement precision of idle pedal position is improved, but device complexity increases

Engineering Contradiction:
Improveaccuracy of idle pedal position determinationVSAvoidcomplexity of brake control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment mechanisms with software-based calibration and offset adjustments. Instead of requiring physical recalibration of the LVDT or mechanical components, the system uses software to compensate for installation variations, significantly reducing device complexity while maintaining high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If both hardware and software threshold voltages are implemented, then reliability of braking control is improved by preventing incorrect braking, but the system requires more complex calibration procedures

Engineering Contradiction:
Improvereliability of braking force applicationVSAvoidease of calibration
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs calibration and offset adjustment as preliminary actions during the installation phase. By completing the software configuration and threshold setting before the aircraft enters service, the system ensures reliable operation without requiring complex calibration procedures during maintenance or operation. This preliminary setup simplifies the overall ease of manufacture and deployment.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution ensures accurate and reliable application of braking forces by accounting for installation variations, reducing the risk of incorrect braking due to tolerances or incidental bumps, and allowing for precise calibration of the software threshold voltage based on actual installation conditions.

Implementation Method 1

A linear variable differential transformer ('LVDT') may be coupled to the brake pedal assembly. The LVDT may output a voltage based on a position of the brake pedal.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2979942B1Systems and methods for aircraft brake sensors
Publication Date: 2019.12.25 GOODRICH CORP
  • EP2979942B1 patent drawingFigure 1
  • EP2979942B1 patent drawingFigure 2

AI summary

An aircraft brake system may include a linear variable differential transformer ("LVDT"). A brake control unit ("BCU") may measure an output voltage from the LVDT. The BCU may include a hardware module, a software module, and an offset module. The hardware module may include a preprogrammed threshold voltage. The output voltage may be measured, and an offset voltage may be determined and stored in the offset module. The software module may measure the sum of the output voltage and the offset voltage. In response to the hardware module and the software module indicating that the threshold voltage has been reached, the BCU may allow braking of the aircraft.